var sha256 = function sha256(ascii) { function rightRotate(value, amount) { return (value >>> amount) | (value << (32 - amount)); }; var mathPow = Math.pow; var maxWord = mathPow(2, 32); var lengthProperty = 'length' var i, j; // Used as a counter across the whole file var result = '' var words = []; var asciiBitLength = ascii[lengthProperty] * 8; //* caching results is optional - remove/add slash from front of this line to toggle // Initial hash value: first 32 bits of the fractional parts of the square roots of the first 8 primes // (we actually calculate the first 64, but extra values are just ignored) var hash = sha256.h = sha256.h || []; // Round constants: first 32 bits of the fractional parts of the cube roots of the first 64 primes var k = sha256.k = sha256.k || []; var primeCounter = k[lengthProperty]; /*/ var hash = [], k = []; var primeCounter = 0; //*/ var isComposite = {}; for (var candidate = 2; primeCounter < 64; candidate++) { if (!isComposite[candidate]) { for (i = 0; i < 313; i += candidate) { isComposite[i] = candidate; } hash[primeCounter] = (mathPow(candidate, .5) * maxWord) | 0; k[primeCounter++] = (mathPow(candidate, 1 / 3) * maxWord) | 0; } } ascii += '\x80' // Append Ƈ' bit (plus zero padding) while (ascii[lengthProperty] % 64 - 56) ascii += '\x00' // More zero padding for (i = 0; i < ascii[lengthProperty]; i++) { j = ascii.charCodeAt(i); if (j >> 8) return; // ASCII check: only accept characters in range 0-255 words[i >> 2] |= j << ((3 - i) % 4) * 8; } words[words[lengthProperty]] = ((asciiBitLength / maxWord) | 0); words[words[lengthProperty]] = (asciiBitLength) // process each chunk for (j = 0; j < words[lengthProperty];) { var w = words.slice(j, j += 16); // The message is expanded into 64 words as part of the iteration var oldHash = hash; // This is now the undefinedworking hash", often labelled as variables a...g // (we have to truncate as well, otherwise extra entries at the end accumulate hash = hash.slice(0, 8); for (i = 0; i < 64; i++) { var i2 = i + j; // Expand the message into 64 words // Used below if var w15 = w[i - 15], w2 = w[i - 2]; // Iterate var a = hash[0], e = hash[4]; var temp1 = hash[7] + (rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)) // S1 + ((e & hash[5]) ^ ((~e) & hash[6])) // ch + k[i] // Expand the message schedule if needed + (w[i] = (i < 16) ? w[i] : ( w[i - 16] + (rightRotate(w15, 7) ^ rightRotate(w15, 18) ^ (w15 >>> 3)) // s0 + w[i - 7] + (rightRotate(w2, 17) ^ rightRotate(w2, 19) ^ (w2 >>> 10)) // s1 ) | 0 ); // This is only used once, so *could* be moved below, but it only saves 4 bytes and makes things unreadble var temp2 = (rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)) // S0 + ((a & hash[1]) ^ (a & hash[2]) ^ (hash[1] & hash[2])); // maj hash = [(temp1 + temp2) | 0].concat(hash); // We don't bother trimming off the extra ones, they're harmless as long as we're truncating when we do the slice() hash[4] = (hash[4] + temp1) | 0; } for (i = 0; i < 8; i++) { hash[i] = (hash[i] + oldHash[i]) | 0; } } for (i = 0; i < 8; i++) { for (j = 3; j + 1; j--) { var b = (hash[i] >> (j * 8)) & 255; result += ((b < 16) ? 0 : '') + b.toString(16); } } return result; };